1. Field of the Invention
This invention generally relates to improving the corrosion and wear resistance of aluminum honeycomb core panel construction by modifying the surface composition and properties of sheet material used to fabricate this type of construction.
2. Description of the Related Art
The use of ion beams to modify the near-surface physical and chemical properties of metals to improve their corrosion and wear resistance is well known. U.S. Pat. No. 5,224,249, for example, discloses an ion implantation process for increasing the corrosion resistance of honeycomb core panel construction used in the fabrication of aircraft wings, fuselage, and other structural framework. During this process, sheet metal used to construct the core and outer skin layers of the honeycomb core panel construction is bombarded with a high-intensity beam of metallic ions. These ions strike the surface of the sheet metal and become embedded therein to a predetermined depth. Atoms of the sheet metal intermix with the metallic ions to create a surface alloy having enhanced corrosion and wear resistance properties. U.S. Pat. No. 4,743,308 discloses a similar process for conditioning the surface of titanium parts used in the construction of human body joint implants.
Conventional ion implantation techniques have a number of drawbacks. First, the high-intensity beam of metallic ions conventionally needed to implement the ion implantation process is difficult to generate and maintain for any significant length of time. Treating a metal workpiece of any significant size therefore becomes a time consuming task. Second, developing an ion beam made of metallic ions, as opposed to non-metallic ions such as the ions from a gas, is expensive. For at least these two reasons, ion implantation as a means of enhancing the corrosion and wear resistance properties of metals is impractical for use in an industrial setting where cost and high volume production are of paramount importance.
The discovery of cheaper, more efficient techniques for increasing the corrosion and wear resistance of metals, and especially aluminum metals used to fabricate honeycomb core panel construction, continues to be an important concern. Existing techniques such as ion implantation have proven to be inadequate in terms of cost and ability to meet mass production demands. A need therefore exists for a process for improving the corrosion and wear resistance properties of aluminum honeycomb metals which is economical to implement and able to meet the high volume production demands of industry.